I have started looking for a full suspension mtb but honestly i have no idea what i'm doing. Is there any good Full suspension mtb for around 3000$? Is it possible to upgrade the components if i feel that mountainbiking is for me? I'm looking for any tips or/and advice on what to get and what's good about it.
I have looked at Merida One-Twenty 9. 600 and Giant Trance 3, but like i said before, i know nothing so i have no clue what to look for in a good mtb. Would really appreciate some help.

Thanks!